dxx-rebirth/common/include/compiler-poison.h
Kp 916eb7a0f9 Extend DXX_CHECK_VAR_IS_DEFINED to work in ASan mode
When AddressSanitizer is enabled, include code to read from the checked
variable, to force AddressSanitizer to perform an accessibility check.
2020-12-27 22:03:09 +00:00

169 lines
4.4 KiB
C++

#pragma once
#if DXX_HAVE_POISON
#include <algorithm>
#endif
#include <memory>
#if DXX_HAVE_POISON_VALGRIND
#include <valgrind/memcheck.h>
#endif
/* Inform Valgrind that the memory range contains writable but
* unreadable bytes.
*
* On non-Valgrind runs, this is a no-op.
*/
template <typename T>
static inline void DXX_MAKE_MEM_UNDEFINED(T *b, unsigned long l)
{
(void)b;(void)l;
#if DXX_HAVE_POISON_VALGRIND
VALGRIND_MAKE_MEM_UNDEFINED(b, l);
#define DXX_HAVE_POISON_UNDEFINED 1
#endif
}
template <typename T>
static inline void DXX_CHECK_MEM_IS_DEFINED(const T *const b, unsigned long l)
{
(void)b;(void)l;
#if DXX_HAVE_POISON_VALGRIND
VALGRIND_CHECK_MEM_IS_DEFINED(b, l);
#endif
}
/* Convenience function to invoke
* `DXX_MAKE_MEM_UNDEFINED(T *, unsigned long)`
*/
template <typename T>
static inline void DXX_MAKE_MEM_UNDEFINED(T *b, T *e)
{
unsigned char *bc = reinterpret_cast<unsigned char *>(b);
DXX_MAKE_MEM_UNDEFINED(bc, reinterpret_cast<unsigned char *>(e) - bc);
}
/* Convenience function to invoke
* `DXX_CHECK_MEM_IS_DEFINED(T *, unsigned long)` for exactly one instance
* of `T`.
*/
template <typename T>
static inline void DXX_CHECK_VAR_IS_DEFINED(const T &b)
{
const unsigned char *const bc = reinterpret_cast<const unsigned char *>(std::addressof(b));
DXX_CHECK_MEM_IS_DEFINED(bc, sizeof(T));
#if DXX_HAVE_POISON
#ifdef __SANITIZE_ADDRESS__
#define DXX_READ_BUILTIN_TYPE_IF_SIZE(TYPE) \
if constexpr (sizeof(T) == sizeof(TYPE)) \
{ \
asm("" :: "rm" (*reinterpret_cast<const TYPE *>(bc))); \
} \
else \
DXX_READ_BUILTIN_TYPE_IF_SIZE(uintptr_t)
DXX_READ_BUILTIN_TYPE_IF_SIZE(uint64_t)
DXX_READ_BUILTIN_TYPE_IF_SIZE(uint32_t)
DXX_READ_BUILTIN_TYPE_IF_SIZE(uint16_t)
DXX_READ_BUILTIN_TYPE_IF_SIZE(uint8_t)
#undef DXX_READ_BUILTIN_TYPE_IF_SIZE
{
auto i = bc;
auto e = reinterpret_cast<const unsigned char *>(bc + sizeof(T));
for (; i != e; ++i)
asm("" :: "rm" (*(i)));
}
#endif
#endif
}
/* Convenience function to invoke
* `DXX_MAKE_MEM_UNDEFINED(T *, unsigned long)` for exactly one instance
* of `T`.
*/
template <typename T>
static inline void DXX_MAKE_VAR_UNDEFINED(T &b)
{
unsigned char *const bc = reinterpret_cast<unsigned char *>(std::addressof(b));
DXX_MAKE_MEM_UNDEFINED(bc, sizeof(T));
}
/* If enabled, overwrite the specified memory range with copies of value `v`.
* In poison=overwrite builds, this is always enabled.
* In poison=valgrind builds, this is enabled if running under Valgrind.
*
* If disabled, this is a no-op.
*/
template <typename T, typename V>
static inline void DXX_POISON_MEMORY_RANGE(T b, T e, const V &v)
{
#if DXX_HAVE_POISON
int store = DXX_HAVE_POISON_OVERWRITE;
#if DXX_HAVE_POISON_VALGRIND
if (!store)
store |= RUNNING_ON_VALGRIND;
#endif
if (!store)
return;
std::fill(b, e, v);
#else
(void)b;(void)e;(void)v;
#endif
}
/* Poison a memory range, but do not mark it as unreadable. This is
* necessary when poisoning a buffer that will be written to the file or
* to a network peer and some of the poisoned fields are expected not to
* be updated (but cannot be removed from the source because the layout
* is mandatory).
*/
template <typename T, typename V>
static inline void DXX_POISON_DEFINED_MEMORY(T b, unsigned long l, const V &v)
{
DXX_POISON_MEMORY_RANGE(b, b + l, v);
}
/* Poison a memory range, then mark it unreadable.
*/
template <typename T>
static inline void DXX_POISON_MEMORY(T b, unsigned long l, const uint8_t v)
{
DXX_POISON_DEFINED_MEMORY(b, l, v);
DXX_MAKE_MEM_UNDEFINED(b, l);
}
/* Convenience function to invoke
* `DXX_POISON_MEMORY(T &, unsigned long, V)`
*/
template <typename T>
static inline void DXX_POISON_MEMORY(T b, T e, const uint8_t &&v)
{
DXX_POISON_MEMORY_RANGE(b, e, v);
DXX_MAKE_MEM_UNDEFINED(b, e);
}
/* Convenience function to invoke
* `DXX_POISON_MEMORY(T &, unsigned long, V)` for exactly one instance
* of `T`.
*/
template <typename T>
static inline void DXX_POISON_VAR(T &b, const uint8_t v)
{
DXX_POISON_MEMORY(reinterpret_cast<unsigned char *>(std::addressof(b)), sizeof(T), v);
}
/* Convenience function to invoke
* `DXX_POISON_DEFINED_MEMORY(T &, unsigned long, V)` for exactly one
* instance of `T`.
*/
template <typename T>
static inline void DXX_POISON_DEFINED_VAR(T &b, const unsigned char v)
{
DXX_POISON_DEFINED_MEMORY(reinterpret_cast<unsigned char *>(std::addressof(b)), sizeof(T), v);
}
#ifndef DXX_HAVE_POISON_UNDEFINED
#define DXX_HAVE_POISON_UNDEFINED 0
#endif